Polyolefins are produced into extrusion molded articles, injection molded articles, blow molded articles, films or sheets for various purposes because of their excellent processability, chemical resistance, electrical properties and mechanical properties.
Polyolefins, however, are poor in affinity with various polar substances, such as metals, and hard to be bonded to polar substances or to be blended with polar resins because they do not have a polar group in the molecule, in other words, they are a non-polar resin. Molded articles of polyolefin have a hydrophobic surface, and therefore need to be compounded with, for example, a surface-active agent of low molecular weight for the applications requiring anti-fogging and antistatic properties. This can sometimes cause problems that, for example, the surface is contaminated by bleeding-out of the surface-active agent.
Polyolefins have been expected to have a variety of properties recently. For example, polyolefins are required to be excellent in heat resistance and, as soft polyvinyl chloride, to have a soft texture.
Various methods have been attempted to improve the properties of polyolefin. Examples of such methods include adjusting the monomer type and the molar ratio, changing the arrangement of monomers, for example, randomly or blockwise, and graft copolymerizing a polyolefin with a polar monomer.
When a polyolefin is graft copolymerized with a polar monomer, a method where the polyolefin is reacted with a radically polymerizable monomer in the presence of a radical initiator is commonly employed. The graft copolymer obtained by such a method often contains a homopolymer of the radically polymerizable monomer and an unreacted polyolefin, and is ununiform in graft structure. Additionally, the graft polymerization involves a crosslinking reaction and a decomposition reaction of polymer chains, thereby widely altering the properties of polyolefin in many cases.
International publication No. WO98/02472 refers to synthesis of a block polymer of a polyolefin and a polar polymer without involving the crosslinking and decomposition reactions by disclosing the method where a boron compound is added to a polyolefin having an unsaturated bond in the terminal position, oxidized by oxygen to form an active species for radical polymerization and thereafter radically polymerized.
The present inventors made an earnest study in light of the prior art and found that a specific block copolymer comprising a polyolefin segment and a functional segment can solve the above problems and also found a process for producing such a block copolymer.
With respect to the process for producing a block (co)polymer comprising two different polymer segments, JP-A-60(1985)/252614, JP-A-60(1985)/252623, JP-A-5(1993)/503546, JP-A-8(1996)/92338 and JP-A-9(1997)/87343 disclose the method involving living polymerization. JP-A-60(1985)/252614 discloses the process for producing a block copolymer comprising a polyolefin segment and a polymethacrylic ester segment by living polymerization. The process involving living polymerization produces only one polymer per catalyst active point, with the molecular weight distribution (Mw/Mn) of polyolefin being approximately 1. The more polymers are obtained per one catalyst active point, the more preferable costwise. It is preferable in view of molding and processing of polymers that the polyolefin segment have a large molecular weight distribution (Mw/Mn).
On the production of a block copolymer comprising a polyolefin segment and a polymethacrylic ester segment, International Publication No. WO98/02472 discloses the method of producing the polymethacrylic ester segment by radical polymerization. This method, however, has a problem that the polymerization, in particular, the stereoregularity and the copolymerizability of the polymethacrylic ester are hard to control because the methacrylic ester is radically polymerized.
The present inventors made an earnest study in light of the prior art and succeeded in converting the end of a specific polyolefin to a specific group and in anionically polymerizing a (meth)acrylic ester in the presence of the polyolefin containing a specific group in the terminal position. They also found that the polymerizability can be controlled easier in the anionic polymerization in comparison with the radical polymerization and that the stereoregularity and the copolymerizability of poly(meth)acrylic ester can be controlled as well.
The inventors additionally found that the block copolymer comprising a polyolefin segment and a functional segment is ideal for various uses, such as bonding; molded articles, e.g., construction and civil engineering materials, automobile interior and exterior parts, gasoline tanks, electric and electronic parts, medical and sanitary products, miscellaneous molded articles, environmentally degradable resin molded articles, films and sheets; modifiers and dispersions.
Compositions comprising a base polymer, such as ethylene/vinyl acetate copolymer or styrene block copolymer, and a tackifier resin have been conventionally used as a hot melt adhesive. However, such a resin is not sufficient in compatibility with a tackifier resin to make, in some cases, the adhesion inferior. The hot melt adhesives have been moreover commercially demanded to have excellent thermoresistant adhesion and thermoresistant creep characteristics. The present inventors made an earnest study in light of the prior art and, as a result, it has been found that the block copolymer comprising a polyolefin segment and a functional segment, and the composition comprising said copolymer and a tackifier resin have excellent thermoresistant adhesion and thermoresistant creep characteristics.
Various synthetic resins, such as polyolefin, have been used as a material of molded articles for construction and civil engineering, e.g., floor coverings, sheets, gaskets, sealants and asphalt modifiers. The floor coverings are required to have impact resistance and mar resistance. The sheets are required to be flexible and resistant to pinholes and penetration. The gaskets and the sealants are required to have flexibility. The asphalt modifiers are desired to be heat resistant and compatible with asphalt. The present inventors made an earnest study on the molded articles for construction and civil engineering which can satisfy the above requirements and, as a result, it has been found that the molded articles for construction and civil engineering, which comprises the block copolymer comprising a polyolefin segment and a functional segment, or the olefin polymer composition comprising said copolymer can meet the above requirements.
Thermoplastic resins, such as polyolefins, polyesters, polyamides and polyacetals, have been produced into injection molded articles, blow molded articles, films or sheets to be used for many purposes because they have excellent processability, chemical resistance, electrical properties and mechanical properties. However, thermoplastic resins are sometimes insufficient in the balance of properties, such as transparency, rigidity, impact resistance and moldability, depending on the use. In order to improve the molded articles comprising such thermoplastic resins in the balance of properties, such as transparency, heat resistance, impact resistance and moldability, a method where a thermoplastic resin is blended with a modifier, e.g., ethylene/α-olefin copolymer, to make a composition is known. However, thermoplastic resins blended with a conventional modifier are sometimes unsatisfactory in the balance between rigidity, surface hardness and impact resistance. As such, automobile interior and exterior parts and gasoline tanks, in which resins or resin compositions excellent in rigidity, impact resistance, oil resistance and heat resistance are used, have been desired. The present inventors made an earnest study in light of the prior art and, as a result, it has been found that the automobile interior and exterior parts and the gasoline tanks comprising the block copolymer comprising a polyolefin segment and a functional segment, or the composition comprising said copolymer can meet the above requirements.
Various synthetic resins, e.g., polyolefins, have been conventionally used as a material of electric and electronic parts, such as wire-coating materials, gaskets used in a refrigerator or the like, optical materials, e.g., optical disk substrate, magnetic recording materials, magnetic recording binders, binders for a plastic magnet, water-absorbing sealants, solid polyelectrolytes, electromagnetic wave shields and housings for electric and electronic parts. The wire-coating materials are required to be electrically insulating stably for a long period of time, flame retardant, extrudable at a high rate and of high breakdown voltage. The gaskets for home appliances are required to have profile extrudability, expansion moldability, small compression shrinkage and flexibility. The optical materials are required to have transparency, mechanical strength and heat resistance. The magnetic recording materials are required to have magneto-optical responsiveness. The magnetic recording binders are required to have fillability and small magnetostriction. The solid polyelectrolytes are required to have low water-absorption, high ionic conductance and chemical stability. The electromagnetic wave shields are required to be weatherable for a long period of time and to depress the deterioration of shielding properties. The present inventors made an earnest study on the electric and electronic parts satisfying such requirements and, as a result, it has been found that the electric and electronic parts, in which the block copolymer comprising a polyolefin segment and a functional segment or the composition comprising said copolymer is used, can meet the above requirements.
Many polymer materials have been used in medical and sanitary products. For example, nonwoven fabrics, represented by the spunbond nonwoven fabric, have been used for various purposes and been required to have improved properties according to the purpose. Particularly, nonwoven fabrics used in, for example, a gather on a paper diaper, a part of sanitary products, such as a sanitary napkin, and a base of compress, are required to have water resistance and to be excellent in water vapor permeability. Depending on the place they are applied to, nonwoven fabrics are further required to be excellent in stretching properties. The proper strength to go through molding processes in the industrial production is additionally needed. Electrets charging a polymer material can keep the electrical charge semipermanently while generating an electric field. Under favor of the electric field, the electrets have been used in medical and sanitary applications, such as a bandage and an adhesive plaster and in absorption of dust in the air. Polytetrafluoroethylene and polyvinylidene fluoride, although conventionally known as a polymer to be a material of electrets, have a problem that the moldability is inferior. There has been proposed a method of preparing electrets, where a polyethylene is compounded with a small amount of modified polyethylene which has been graft copolymerized with an unsaturated carboxylic acid to improve the electrical charge properties, thereby easing the electrical charge. This method achieves only low electrical charge properties, and the electrets produced are to be improved in its effects and durability. The present inventors made an earnest study on the medical and sanitary products that can satisfy the above requirements or solve the problems and, as a result, it has been found that the medical and sanitary products, in which the block copolymer comprising a polyolefin segment and a functional segment, or the composition comprising said copolymer is used, are able to satisfy the above requirements.
Thermoplastic resins, such as polyolefins, polyesters, polyamides and polyacetals, are often insufficient, depending on the uses as miscellaneous goods requiring good design, in the balance between properties, such as impact resistance, mar resistance, printability, coating properties, low-temperature flexibility and moldability. For improving molded articles comprising the thermoplastic resin in the balance between properties, such as impact resistance and moldability, a method where a thermoplastic resin is blended with a modifier, e.g., ethylene/α-olefin copolymer, to make a composition is known. Conventional modifiers, however, are unsatisfactory in improving the balance between rigidity, surface hardness and impact resistance in some cases depending on the use. The present inventors made an earnest study on the miscellaneous molded article satisfying the above requirements and, as a result, it has been found that the miscellaneous molded article comprising the block copolymer comprising a polyolefin segment and a functional segment, or the composition comprising said copolymer is superior in any of the properties of impact resistance, heat resistance, mar resistance, transparency, coating properties, printability, adhesion and low-temperature flexibility.
Resins, such as polyolefins, polystyrenes, polyvinyl chlorides, polyesters and polyamides, are chemically stable and remain in the natural environment semipermanently once they are disposed to cause waste problems, e.g., damage to the landscape. Resins which are environmentally degradable owning to the living metabolism have been developed in order to solve such problems. Examples of such resins include aliphatic polyesters, such as a polylactic acid, a polyglycol acid, a poly-β-hydroxy butyric acid, poly-ε-caprolactone, a polybutylene succinate and a polyethylene succinate; a polyvinyl alcohol and a polyethylene glycol. Of these, aliphatic polyesters have been practically used because of, for example, its moldability. These resins, however, are insufficient in heat resistance and mechanical strength, etc., for practical uses. For example, a polylactic acid has drawbacks in that the heat resistance is hard to be attained because of its low crystallization rate, and that uses as a container where a practical strength is required are not expected owning to inferior toughness. And, poly-ε-caprolactone has a low melting point and is not practical, although high in impact resistance. As a result of an earnest study made by the present inventors in light of the prior art, it has been found that the block copolymer comprising a polyolefin segment and a functional segment, and the composition comprising said copolymer can produce an environmentally degradable resin molded article having excellent practical properties, such as heat resistance and impact resistance.
Although polyolefins are excellent in moldability and molded articles thereof have heat resistance, such molded articles have drawbacks, when used as a packaging material, in that contents are scratched or look less beautiful than they really are because of poor flexibility and low transparency of the polyolefin. Therefore, attempts to improve the flexibility and the transparency of polyolefins have been made by, for example, laminating a soft composition, e.g., vulcanized rubber, on an outer surface of a multilayered plastic container, or laminating a vinyl acetate resin on an outer surface of a multilayered container. The above methods, however, can not attain sufficient properties and are required to achieve improved anti-fogging properties, tackiness or the like depending on the use of the molded article. The present inventors made an earnest study in light of the prior art and, as a result, it has been found that the films and the sheets comprising the block copolymer comprising a polyolefin segment and a functional segment, or the composition comprising said copolymer are excellent in any of flexibility, transparency, tackiness, anti-fogging properties and heat resistance.
Thermoplastic resins, such as polyolefins, polyesters, polyamides and polyacetals, are sometimes insufficient in the balance between properties, such as transparency, rigidity, impact resistance and moldability, depending on the use. For improving molded articles comprising the thermoplastic resin in the balance between properties, such as transparency, heat resistance, impact resistance and moldability, a method where the thermoplastic resin is blended with such a modifier as an ethylene/α-olefin copolymer to make a composition is known. Conventional modifiers, however, cause a problem that the resulting molded article is unsatisfactory in the balance between rigidity, surface hardness and impact resistance in some cases depending on the use. The blend of an olefin rubber, such as ethylene/propylene rubber or ethylene/propylene/non-conjugated diene rubber, with a natural rubber (NR) or a diene rubber, such as styrene/butadiene rubber (SBR), can improve the weathering resistance and the heat resistance of the natural rubber or the diene rubber. However, their compatibility is so bad that the co-crosslinkability is insufficient, resulting in inadequate effects of modification. Thermosetting resins, such as phenolic resins, epoxy resins, urea resins and melamine resins, have been processed through cast molding or the like for various purposes under the favor of their excellent heat resistance, chemical resistance, mechanical characteristics and electrical characteristics. These resins, however, are insufficient in the balance between moldability and impact resistance, etc. Therefore, development of a modifier which can improve the moldability and the impact resistance of the thermosetting resins, has been desired. Lubricating oils generally contain a viscosity index improver to allow operation unaffected by any temperatures low or high. Lubricating oils further contain, for example, an abrasion-resistance agent, an extreme pressure agent, an antioxidant, a corrosion inhibitor, a detergent-dispersant or an emulsifying agent for the purpose of improving the properties of the lubricating oils under severe conductions. These additives contain polar groups in so large amounts that the compatibility thereof with a base oil, e.g., hydrocarbon base oil, is bad. The present inventors made an earnest study in light of the prior art and, as a result, it has been found that the modifier comprising the block copolymer comprising a polyolefin segment and a functional segment, or the composition comprising said copolymer is excellent in properties of modifying any of impact resistance, heat resistance, weathering resistance, mar resistance, transparency, coating properties, adhesion, low-temperature flexibility, fluidity and dispersion properties.
Polyolefins, such as polypropylene and polyethylene, are occasionally insufficient in heat resistance, rigidity and strength depending on the use. In such a case, polyolefins are reinforced with a filler, e.g., talc and glass fiber. However, polyolefins are low in polarity and, contrarily, most fillers have polarity. Therefore, the filler is not sufficiently dispersed in a polyolefin and the adhesion in the interface of the filler and the polyolefin is low. This can frequently cause a problem that the effect of reinforcement with a filler is not fully attained. As such, a silane coupling agent or a titanate coupling agent is incorporated therein at the time of melt-compounding, or a filler is treated on the surface with a higher fatty acid or the like, which although does not produce satisfactory effects. Additionally, attempts have been made to obtain a composite material in which organic polymer materials are inserted between silicate layers constituting phyllosilicate. For example, phyllosilicate is treated with an amino acid or a nylon salt, and a monomer is incorporated therein and polymerized, thereby obtaining a clay mineral/polyamide resin composition (cf. JP-B-58(1983)/35211 and JP-B-58(1983)/35542). Or, a polyamide-containing resin is incorporated in silicate layers constituting phyllosilicate, which have a thickness of 7 to 12 Å and an interlaminar distance of at least 30 Å, thereby obtaining a composite material wherein a part of polymer chains of the polyamide is ionically bonded to silicate layers, which is reported in JP-A-62(1987)/74957 as a composite material wherein a part of polymer chains of polyamide is tonically bonded to silicate layers. On the other hand, with respect to the polyolefins, it is now under consideration to use phyllosilicate as a filler, which is finely dispersed by melt-kneading the phyllosilicate treated with an alkylamine swelling agent together with a modified polyolefin and a polyolefin. This method, however, does not produce sufficient effects of reinforcement. As a result of an earnest study made by the present inventors in light of the prior art, it has been found that the block copolymer comprising a polyolefin segment and a functional segment, and the composition comprising said copolymer can produce excellent effects of improvements in reinforcement and dispersion properties.
Polyolefins, such as ethylene (co)polymers and propylene (co)polymers, are poor in affinity with other resins and metals. Therefore, it is hard to bond a polyolefin to other parts. As such, various adhesives have been studied to bond a polyolefin to other resins and metals. Preferably, these adhesives are aqueous to assure working environment. Aqueous resin dispersions of ionomer resins are conventionally known as the aqueous resin dispersions for the bonding of polyethylene. These dispersions, however, do not have sufficient adhesion. Recently, against the backdrop of increased attentions on the environmental problems, there has been a conversion from a polyvinyl chloride (PVC) to a polyolefin along with increased frequency of use of polyethylene or the like. Accordingly, adhesives for the bonding of polyolefin having excellent adhesion have been strongly desired. The present inventors made an earnest study in view of the prior art and, as a result, it has been found that the block copolymer comprising a polyolefin segment and a functional segment, and the composition comprising said copolymer can produce aqueous dispersions having excellent dispersion properties in an aqueous medium and exhibiting high adhesion to polyolefins, metals and polar resins.
A resin dispersion of a modified polyolefin has been proposed, for example, in JP-A-63(1988)/12651, as an adhesive comprising a dispersion in which a polyolefin is dispersed in an organic medium and which is used for bonding polypropylene to a metal, e.g., aluminum. The modified polyolefin, however, is insufficient in dispersion properties in an organic medium and can cause a problem that the dispersion agglomerates in a gel state during a long-term storage in some cases. The present inventors made an earnest study in light of the prior art and, as a result, it has been found that the block copolymer comprising a polyolefin segment and a functional segment, and the composition comprising said copolymer can give an organic-medium dispersion having good dispersion properties and dispersion stability in an organic medium and exhibiting high adhesion to polyolefins, metals and polar resins.